10k SATA vs 15k SCSI Hard Disks...
 

Read this article:
http://www.pugetsystems.com/articles.php?id=19

Interesting... anyone has thoughts?

I think it is moving that way. If you are looking for cutting edge you still go with the SCSI because of the CPU utilization. For anything less you can look at a good SATA system. SATA would certainly be fine for a web front end server.
I wonder how SAS will stack up

I would guess it won't matter much if you are serving tons of dynamic files like php pages as lots of them will be cached. The page was awful blinky for me to read the full article :/

That article is over 14 months old - a lifetime in disk technology so i wonder how they compare now. Our (work) experience is that SATA still lags SCSI - certainly in SAN arrays.

I scanned over the article to the end results so I may have missed something. I did a lot of research before having my new 2x 270 Opteron server custom made with 15k SAS drives, RAID 1 & RAID 10 drive arrays, etc. I had a lot of people telling me to go with the Raptor 10k SATA drives because they were "just as fast" as SCSI but after a lot of research that just isn't true in a heavy data base environment. SCSI or SAS drives have a lot better I/O than SATA.

I would be willing to use fast SATA drives for future web servers but for my database server I won't use anything but SCSI or SAS.

I plan to use 4 x SATA disks in RAID 0 - that should be plenty fast.

Erwin,
Are you using this for data base or web? How many servers are you running now?

David

Its not so much speed, as having the the onboard cpu just for the scsi drives to do lookups. Which is why scsi is, and always has been faster.

No doubt 15,000 RPM SCSI hard drives are faster than 10,000 RPM Serial ATA hard drives. I have both kinds and there is really no comparison... especially when comparing large file transfers.

All I have to say about hard drives is:

RAID RAID RAID RAID

RAID-10 = The way to go for anything (if you can afford it).

If you had to choose between the following for a VERY BUSY DATABASE SERVER, which would you choose?

1. 10k Raptor SATA vs 10k SCSI?

2. 10k Raptor SATA (2) RAID 1 vs 10k SCSI?

3. 10k Raptor SATA (4) RAID 1 vs 10k SCSI?

I'm trying to decide how essential SCSI is for a busy db server.

Also, choose between the following:

4. Dual Processor/ Dual Core Opteron 2.0 4 Gb with 10k Raptor SATA (2) RAID 0 (or RAID 1)

vs

Dual Xeon 2.8 (single cores) 3 Gb with 10k SCSI (no Raid)

for a busy database server???

Is SCSI so much better that it overrides the CPU advantage? Does RAID makes SATA better than SCSI?

Dual for me. I'd also go for the SATA in RAID 1.

10K scsi IMO, you want your database server processors processing sql queries, not lookups to the hardrives.

"a VERY BUSY DATABASE SERVER" => SCSI in RAID10 (better than RAID1, though requires 4 disks), RAID5 would probably be worse as it's slower for many small random writes, which is a typical db workload.

10k SCSI or especially (SAS) Serial Attached SCSI without a second thought

Not exactly fair unless you are talking just raw speed. I look at RAID more for redundancy but as you add drives you will pick up performance boosts, especially in reads. I would still opt for 10k SCSI
Your tempting me now since you have 4 drives.. How good is your RAID card? :p
If you now take the 10k SCSI drives and add a good RAID card you will likely have a great database server.. Very fast if running RAID 10 or even a lot of drives in RAID 5 and full redundancy.

Doc, with all due respect you are asking for trade-offs (IMO) on each this vs. that setup. I mean, if you asked me if I would go with the 10 SCSI (no Raid) with ether a Xeon or Opterson vs. a 10k Raptor SATA RAID 0 setup utilizing a Xeon or Opteron processor it would be easier to decide on but when I look at this my opinion is you handicap your setups. It's like good processor with ok drive setup or ok processor with a good drive setup.

I am no hardware guru but before I just dropped $6,470.00 on a server I studied this stuff pretty hard. I went back and forth with multiple server setups to single power-houses.. I looked at SATA Raptor 10k drives, SATA RAID controllers, SCSI u320 10k & 15k drives and finally learned about SAS 10k & 15k Cheetah, Atlas and other drives.

In the final analysis and my conclusion after reading for literally days on the subject is this: In a database server environment SCSI simply beats all SATA drives on the market today, including the Raptors (which I dearly love for my home PC and would use in a web server), especially when you get into RAID configurations..

And speaking of RAID setups... I studied this and asked everyone under the sun on which is the best... And for a screaming fast database server, the consensus seems to be RAID 10.

Your forums are undeniably large any way you look at them.. Personally, I would not even consider a SATA setup for your databases. You need a good RAID 10 or maybe a 5 setup with a lot of drives for your database server, IMO.

Here are the specifications of the server that I just purchased. It was designed to handle both our web & database needs for the emmediate future. When we need more I will add web sever(s) and transition this server to handle only database usage. When that time comes I will feel comfortable having single or dual opteron 1u server(s) that run a RAID-1 using (2) Raptor drives. Until then, I think it will be plenty.

One thing of note with regards to my server and pricing. It would have been a good deal cheaper if I had not gone with the SAS drives and the RAID card spec'd. I had a really nice RAID 10 setup with (4) 15k Cheetah drives for a little bit over $4,000.00 and would have been an awesome database server. I had plans to use that and also a web server but decided it would be more practical to just build a "monster" to handle our needs for now and save me hosting expenses at this point in time.

Spec's:
2x AMD Opteron 270 Dual-Core socket 940 CPUs (4 cores total)
Supermicro H8DAE dual socket 940 server board
8G DDR-400 PC-3200 ECC Registered, NUMA
Adaptec 4800SAS 8-port hardware SAS RAID controller, 133mhz PCI-X
2x Maxtor Atlas 73-Gig SAS, 15k rpm (RAID-1 for OS)
4x Maxtor Atlas 36-Gig SAS, 15k rpm (RAID-10 for data)
1x Seagate Barracuda 300-Gig IDE, 7200rpm (for backup)
on-board broadcom dual gigabit NICs
Supermicro IPMI 2.0 adapter (AOC-1UIPMI-B)
on-board ATI rage Video, 8M
24x slim CD-ROM; 1.44M Floppy
SuperMicro SC822T-R500RC 2U Rack-mount Chassis
6x Hot-swap HDD Carriers & 1x6 SATA/SAS Backplane
dual SuperMicro 500watt Redundant Power Supplies

Thanks for all the responses and help. :)

I currently run SCSI on all my servers, just being tempted to a different DC with better CPUs but Raptors. Looks like I will need to keep my SCSIs...

Erwin, once you go SCSI, you don't go back. ;)

lol... :banana:

You know, if you could offer me a quad opteron system with like 20 Raptor 10k drives and some really awesome RAID card(s), I might do that.. ;)

The only down-side to SCSI as we all know are the prices for the drives. I think the SAS hard drives for my new server cost more than the dang server. For web hosting companies, it is a lot cheaper to offer the SATA drives and an opteron box than messing with SCSI. I tried and tried to get a few different dedicated server providers to put together a good deal for me using Opterons and SCSI HD's/RAID and every time we tried to work in the SCSI u320 drives and RAID card it priced it way up beyond what I wanted to pay. I'll for sure go with them (10k SATA) when I need new web servers but not for data base.

Ok, I'll shut up now ;)

What do people make of this article?
http://www.pugetsystems.com/articles.php?id=19

Also...

In terms of speed (forgetting about risk/data loss/life span etc), which one would you choose:

1) 10k Raptor NCQ x 4 in RAID 0 setup

OR

2) 10 k SCSI x 1, non-RAID

(note: both disks at 10k)

???

Are all 4 drives part of this RAID 0 array?
I would guess that would create maxium throughput but if one fails, but data loss is a big risk on this setup due to a failure. So maximum on both accounts. ;)

I've done fairly extensive research on the 10K SATA 150MB Raptors vs 10K or 15K SCSI for database purposes.. Basically the Raptors perform much better than any other IDE/SATA drive out there, but the SCSI drives perform much better than the Raptors. So it's like the Raptors get you about 40% of the way to SCSI but you will still suffer. Especially with a lot of small reads. Now if you go to 15K SCSI there is no comparison.

I use RAID5, but I am going to use RAID10 on any future setups. It is also is smart to have a secondary drive outside the RAID array for backups or log files. By using a secondary drive for backup creation, I cut my backup time by about half (and cut it to 1/4 by using incremental backups without compression instead of compressed files). So it went from 4 hours to less than 1 hour. This is useful even if you store your backups off-server (as you should) since the backup creation still usually occurs locally before it is FTP'd off somewhere.

-vissa

Vissa,
In my new server I have a extra 300 Gig HD that is outside the RAID system for this purpose. It has not been racked yet (hopefully Monday) and setup but I wanted to ask you since you seem to have a similar setup, how often you backup outside of the server and if you do it in that data center or another one, or local?

Thanks,
David

David,

I backup to the separate HD nightly (daily, weekly and monthly retained), then every few days or once week off-site to a server at another datacenter. I could have used the datacenter's backup solution but this is free for me and I have the bandwidth to spare (backing up between the 2 servers from different datacenters). Just make sure you use SSH2 for transfers off-site. So if there is an earthquake/fire/etc at a datacenter I'm still ok. :)

-vissa

I like the idea of backing up to a separate server elsewhere.
If there was a catastrophic failure at the primary DC or with the server(s) there, how long would it take to get back online at the secondary DC? Is everything setup and ready to roll as soon as you change IP's ?

What about the server spec's at DC #2? Are you using a lower end server or do you really need to have a dupe of the primary? That would be quite expensive for me but having a lower end one (maybe a single Opteron 270 with SATA RAID 1) could be feasible.

This would be a cool topic for a new thread in the BB section: What type of redundancy / fail-over do you have for your big board.

Single disk performance, 150GB Raptor X and two 74GB Raptors vs two 10K SCSI disks:
http://www.fcenter.ru/img/article/hd...AHFD/82975.png
http://www.fcenter.ru/img/article/hd...AHFD/82976.png

Raptor X is targeted at desktop users (modders) though, there's also a server version which should have the appropriate firmware tweaks.

I'm looking for a host that offers 15k SCSI drives now. :)

Is 15k SCSI with RAID0+1 enough, or should I look as SAS as well?

I would go with the 15,000 RPM drives for sure, but the u320 SCSI setup will be fine. SAS is new and in the expensive stages. I don't know how much of an increase it actually gives right now. I went for it more out of future upgrade compatibility than anything else.